I am learning NodeJS and the course I’m following has several projects, arranged by sections. I have all the projects under one main folder, which is also a git repository.
Each of these subfolders in the main folder is a node project by itself, complete with package.json and related dependencies in node_modules. The problem is when I tried to push the node app in one such folder(todo-api) to heroku, I get the following error –
remote: Compressing source files... done. remote: Building source: remote: remote: ! No default language could be detected for this app. remote: HINT: This occurs when Heroku cannot detect the buildpack to use for this application automatically. remote: See https://devcenter.heroku.com/articles/buildpacks remote: remote: ! Push failed remote: Verifying deploy... remote: remote: ! Push rejected to agile-forest-32749. remote: To https://git.heroku.com/agile-forest-32749.git ! [remote rejected] master -> master (pre-receive hook declined) error: failed to push some refs to 'https://git.heroku.com/agile-forest-32749.git'
This is the directory structure for the project –
I decided to refactor out the todo-api subfolder into a new project all by itself, and this time the push to Heroku works just fine –
I don’t understand why I get the “no default language” error, especially when the node app is exactly the same in both places. Any thoughts?
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Answer
Heroku has a set of default buildpacks, used when it needs to detect the language of your app.
In order to do that detection, it runs the bin/detect command of each of those default buildpacks, until one of them returns a 0 exit code.
This is the command for the node buildpack.
As you can see, it requires a package.json to be located at the root of your app, not in a subfolder.
This is the difference causing your build to fail. You need to put your app at the root of your git repository.